Open positions (last updated 06/2014)

Research / Recherche

My research activities focus on experimentation for the evaluation of
distributed systems in the context of High Performance Computing and Clouds. I work on the design of experimental testbeds (Grid'5000), emulation (Distem emulator), and Open Science and reproducible research.

Projects :

Grid'5000: Member of the bureau, comité d'architectes and comité technique. chief scientist of the Nancy site.

AEN INRIA Hemera: leader of a working group on Completing challenging experiments on Grid'5000

Publications

International journals, conferences and workshops

(Also includes some research reports, but only when there's no corresponding article (yet?))

Tomasz Buchert, Emmanuel Jeanvoine and Lucas Nussbaum.Emulation at Very Large Scale with Distem
SCALE Challenge, held in conjunction with the 14th IEEE/ACM International Symposium on Cluster, Cloud and Grid Computing (CCGRID) (2014)HAL -
Bibtex -
paperslides

Non-academic talks

In another life, I am a Free Software developer, involved mainly in Debian,
where I focus on Quality Assurance (working on infrastructure like Ultimate Debian Database and on
archive-wide testing, like ensuring that all packages in Debian can be rebuilt
from source or can still be installed. I am also known for my work on improving
collaboration between Debian and Ubuntu (see this LWN article, for
example). And I enjoyed writing some applications in Ruby to scratch some
itches, like feed2imap.

Supports de cours divers

Liens utiles

Useful Resources

Code

Katapult: tool for automating the deployment of nodes using Kadeploy. homepage.

NISTNet on recent Linux kernels (2.6.26+). More.

The original NISTNet
doesn't work on recent Linux kernels. There are some instructions (and a patch)
to make it work on more recent kernels available here,
but even this patch fails to work with more recent Linux kernels (apparently it
worked until Linux 2.6.24). Here is an updated patch that is known
to work with Linux 2.6.26. It applies to nistnet.2.0.12c.tar.gz,
and the normal installation instructions work fine, provided that you install
the necessary build dependencies (for Debian, at least x-dev libxt-dev
libxmu-headers libxaw7-dev libc6-dev-i386 xmkmf xaw3dg-dev).

Another problem is that recent distribution kernels enable HPET, which
breaks NISTNet. You need to recompile your kernel to disable it. Here is a patch against Debian's 2.6.26
kernel configuration that is known to work (a simpler diff might work too).

Note: if you are a Grid'5000 user, a sid-x64-base-1.1-nistnet
image is available on Orsay (user lnussbaum). Log in as root,
cd nistnet-3.0a, run make install,
modprobe nistnet, and use cnistnet.

iperf's reverse mode. More.

iperf is a popular tool to measure network throughput. However, it
can only be used to measure throughput from the iperf client to the iperf
server. This is a problem when one wants to measure the throughput in both
directions, and one of the hosts is behind a NAT/firewall. This patch adds a
reverse mode, where the data is transfered from the server to the
client, allowing to measure the download throughput. This mode is
enabled by specifying the -2 option. The patch has been submitted to
iperf's authors, but hasn't been included yet.

With SCTP, computing CRC32 checksums is known to add a signifiant overhead.
Unfortunately, most NICs don't support offloading that computation. To be able
to achieve Gigabit-grade bandwidth with SCTP with current hardware, it is
required to disable SCTP checksumming. This is only possible by manually
modifying the SCTP implementation. This patch adds a module option
(no_checksums) that allows to easily disable checksums
computation.

Note: This breaks protocol compliance. You won't be able to
communicate with hosts where checksums are enabled.